In conventional technique, an image display apparatus for a vehicle is well-known. As to this apparatus, a plurality of cameras is loaded onto a vehicle, and each camera images the front side or the back side of the vehicle along the moving direction. Briefly, by imaging a region hard for a driver to view during the vehicle's running, this image is displayed in order for the driver to visually recognize the region. Furthermore, while another vehicle is running at the back of the driver's vehicle along the same direction, irregular approach or behavior of another vehicle is monitored by imaging another vehicle. Alternatively, when the vehicle is driven backward to park, an image of the back side of the vehicle is displayed in order for the driver to supplement the driving.
On the other hand, recently, a camera-performance improves day by day, and a camera having a high resolution and an imaging at night is used. Accordingly, when the front side or the back side of a user's vehicle is imaged by a camera loaded onto the vehicle, for example, a person who rides in another vehicle running at the front or back of the vehicle along the same direction is often imaged. Furthermore, a document located in a cabin of another vehicle or a number-plate of another vehicle is often imaged.
However, an image by the camera often includes a region related to personal privacy such as a person's face or a number plate. Accordingly, when an image by a camera having high ability above human's eyesight is stored, the user may be accused by a crime such as an infringement of privacy or an imaging on condition that an object is unconscious of the imaging.
If the camera-performance further improves and an image having details and clearness can be seen, in near future, how to protect personal information in a cabin of another vehicle (moving at the front or back of the user's vehicle along the same direction) can be a problem. An object side cannot be aware whether the high performance-camera has a zoom function or a low light imaging function. Accordingly, the object side cannot decide whether an imaging by the camera is a behavior to supplement the driving or an imaging behavior on condition that the object is unconscious of the imaging. Furthermore, by improvement of the technique or rise of the needs, it is sufficiently expected that a camera loaded on to a vehicle (Hereinafter, it is called on-vehicle camera) has a higher fundamental performance and an imaging at night is often used.
Accordingly, when the on-vehicle camera to assist the driving is widely used, if the camera always monitors surroundings of the vehicle, a cabin of another vehicle can be continually watched from a user's vehicle while another vehicle is running at the side or back of the user's vehicle, and a person who rides in another vehicle has a bad feeling. Accordingly, as to on-vehicle equipment having the camera, in near future, means for protecting the personal information is necessary.
In JP-A 2008-9761 (Kokai), in order to protect the privacy, an apparatus for recording a cabin-environment is disclosed. As to this apparatus, information to personally specify a driver (For example, image including the driver's face) is masked. In JP-A 2007-164275 (Kokai), an image processing apparatus in a monitoring system is disclosed. As to this apparatus, a number plate part is identified in an image by the camera and concealed in the image. Furthermore, in JP-A 2006-349456 (Kokai), in order to understand a status of the dead angle occurred by another vehicle moving or turning to the right at the front of the user's vehicle, an example to monitor the status using a radar apparatus is disclosed.
However, by considering rise of the camera-performance, even if a face image of a driver or a number plate image is masked in an image of another vehicle, protection of personal information is difficult, and further improvement is desired. Furthermore, when a mask region of a vehicle moving at the front of the user's vehicle along the same direction (Hereinafter, the vehicle is called a first front vehicle) is enlarged, another vehicle moving at the front of the first front vehicle along the same direction (Hereinafter, another vehicle is called a second front vehicle) recognized via a window of the first front vehicle may be often concealed, and a function to assist the driving of the user's vehicle drops. In the same way, when a mask region of a vehicle moving at the back of the user's vehicle along the same direction (Hereinafter, the vehicle is called a first back vehicle) is enlarged, another vehicle moving at the back of the first back vehicle along the same direction (Hereinafter, another vehicle is called a second back vehicle) recognized via a window of the first back vehicle may be often concealed, and a function to assist the driving of the user's vehicle drops. Furthermore, usage of the radar apparatus requires high cost.
As mentioned-above, in a conventional image display apparatus for a vehicle, a part (For example, a face or a number plate) of the image by the camera is masked in order to protect the personal information. However, if the mask area is enlarged, the second front vehicle or the second back vehicle may be often concealed. As a result, a function to assist the driving of the user's vehicle drops.